Tools

"... We prove optimal, up to an arbitrary ffl? 0, inapproximability results for Max-Ek-Sat for k * 3, maximizing the number of satisfied linear equations in an over-determined system of linear equations modulo a prime p and Set Splitting. As a consequence of these results we get improved lower bounds for ..."

for the efficient approximability of many optimization problems studied previously. In particular, for Max-E2-Sat, Max-Cut, Max-di-Cut, and Vertex cover. Warning: Essentially this paper has been published in JACM and is subject to copyright restrictions. In particular it is for personal use only.

"... We describe a real-time computer vision and machine learning system for modeling and recognizing human behaviors in a visual surveillance task [1]. The system is particularly concerned with detecting when interactions between people occur and classifying the type of interaction. Examples of interes ..."

of interesting interaction behaviors include following another person, altering one's path to meet another, and so forth. Our system combines top-down with bottom-up information in a closed feedback loop, with both components employing a statistical Bayesian approach [2]. We propose and compare two

"... Driver inattention is one of the main causes of traffic accidents. Monitoring a driver to detect inattention is a complex problem that involves physiological and behavioral elements. Different approaches have been made, and among them Computer Vision has the potential of monitoring the person behind ..."

Driver inattention is one of the main causes of traffic accidents. Monitoring a driver to detect inattention is a complex problem that involves physiological and behavioral elements. Different approaches have been made, and among them Computer Vision has the potential of monitoring the person

"... Machine learning for text classification is the cornerstone of document categorization, news filtering, document routing, and personalization. In text domains, effective feature selection is essential to make the learning task efficient and more accurate. This paper presents an empirical comparison ..."

Machine learning for text classification is the cornerstone of document categorization, news filtering, document routing, and personalization. In text domains, effective feature selection is essential to make the learning task efficient and more accurate. This paper presents an empirical comparison

"... Bridging models, as the BSP, tend to abstract the characteristics of the interconnection networks using a small set of parameters, by dividing the computation in supersteps and organizing the communication in global patterns called h-relations. In this paper we evaluate, through experimental results ..."

Bridging models, as the BSP, tend to abstract the characteristics of the interconnection networks using a small set of parameters, by dividing the computation in supersteps and organizing the communication in global patterns called h-relations. In this paper we evaluate, through experimental results conducted on a wormhole-routed bi-dimensional torus and a quaternary fat-tree with 256 processing nodes, the execution time of three families of h-relations with variable degree of imbalance. We also prove a strong result that links the communication performance of the fat-tree with the BSP abstraction of the interconnection network. Given a generic h-relation, we can provide a value of g that, in the worst case, slightly overestimates the completion time and is very close to optimality.

"... User Generated Content (UGC) is re-shaping the way people watch video and TV, with millions of video producers and consumers. In particular, UGC sites are creating new viewing patterns and social interactions, empowering users to be more creative, and developing new business opportunities. To better ..."

statistical properties of requests and their relationship with video age, and the level of content aliasing or of illegal content in the system. We also provide insights on the potential for more efficient UGC VoD systems (e.g. utilizing P2P techniques or making better use of caching). Finally, we discuss

by
Silviu Maniu, Bogdan Cautis
- In Procedings of the ACM SIGMOD International Conference on Management of Data (SIGMOD, 2012

"... We demonstrate the Taagle system for top-k retrieval in social tag-ging systems (also known as folksonomies). The general setting is the following: users form a weighted social network, which may reflect friendship, similarity, or trust; items from a public pool of items (e.g., URLs, blogs, photos, ..."

applications, in an online context where the social network, the tagging data and even the seekers ’ search ingredients can change at any moment. We also illustrate possible design choices for providing users a fully-personalized and customizable search interface. By this interface, they can calibrate how

"... We formulate and study search algorithms that consider a user’s prior interactions with a wide variety of content to personalize that user’s current Web search. Rather than relying on the unrealistic assumption that people will precisely specify their intent when searching, we pursue techniques that ..."

, and other information about the user such as documents and email the user has read and created. Our research suggests that rich representations of the user and the corpus are important for personalization, but that it is possible to approximate these representations and provide efficient client

"... This paper presents a general, trainable system for object detection in unconstrained, cluttered scenes. The system derives much of its power from a representation that describes an object class in terms of an overcomplete dictionary of local, oriented, multiscale intensity differences between adj ..."

adjacent regions, efficiently computable as a Haar wavelet transform. This example-based learning approach implicitly derives a model of an object class by training a support vector machine classifier using a large set of positive and negative examples. We present results on face, people, and car detection

"... There is evidence from several sources that one cannot treat many-person households as a single decision maker. If this is the case, then factors such as the relative incomes of the household members may affect the final allocation decisions made by the household. We develop a method of identifying ..."

There is evidence from several sources that one cannot treat many-person households as a single decision maker. If this is the case, then factors such as the relative incomes of the household members may affect the final allocation decisions made by the household. We develop a method of identifying